Study of the effect of a potential neuroprotective drug on the dynamics of the cerebral circulation in laboratory animals by laser speckle contrast imaging
Nadezhda V. Golubova,1 Evgeniya S. Seryogina,1 Elena F. Shevtsova,2 Viktor V. Dremin,1,3 Elena V. Potapova,1
1 Research and Development Center of Biomedical Photonics, Orel State University, Russia; 2 IPAC RAS, Biomolecular Screening Laboratory, Russia; 3 College of Engineering and Physical Sciences, Aston University, United Kingdom
Abstract
Dynamic characteristics of blood flow can be obtained by performing wavelet transforms over the raw data of the laser speckle contrast imaging (LSCI). The processing is similar to the laser Doppler flowmetry (LDF) method, which is widely used in the study of microcirculation. However, analysis of oscillations in LSCI data seems to be more promising as it offers full-field imaging and high spatial and temporal resolutions.
All of that makes LSCI applicable in the tasks of studying the effects of various pharma drugs on living organisms. In particular, the study of cerebral blood circulation when a biologically active substance is injected into a laboratory animal would provide valuable data on how the substance affects the microcirculatory system.
The aim of this work was to evaluate the effect of the potential neuroprotective multitarget drug TG-2112х on the temporal dynamics of the cerebral circulation in rats.
All manipulations with the animals are approved by the ethical committee of the Orel State University (protocol No. 10, 16 October 2018).
The experimental setup that implements the LSCI technique was developed to obtain speckle images of the rat cortex. The laser source (785 nm operating wavelength) illuminated the area of interest through a set of diffusers. The backscattered light was collected via a high-resolution CMOS camera. To eliminate single scattering, a polarizer was placed in front of the camera objective. The images were obtained for 50 frames per second and 10 ms exposure time.
Two months old Wistar rats were used in the experiment. Three rats were injected with the biologically active substance dissolved in a DMSO solution. Three more rats were controls, and they were injected only with DMSO solution.
The study protocol included animal’s anesthesia by intramuscular injection of Zoletil/Xyla drug composition and intraperitoneal injection of the required solution. After that, the animal was fixed in a 3D-printed animal stereotaxis to avoid movement artefacts. The physiological parameters of the studied animal were controlled by a special monitoring complex. The images were consistently captured for approximately 20 minutes.
The processed data show differences in the dynamic characteristics of cerebral blood flow in the animals injected with the biologically active substance compared to the control animals injected with the DMSO solution alone.
The study was supported by the Russian Science Foundation under the project №21-15-00325.
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Nadezhda Golubova
Orel State University
Russia
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